• Journal of the Korean Chemical Society
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• 제13권4호
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• pp.309-312
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• 1969

A series of metal ion-2, 5-diamine 1, 4-dihydroxybenzene polymers containing copper(II), nickel(II) or cobalt (II) have been prepared. The structure was postulated on the basis of elementary analysis of polymers. It was found that copper polymer is most likely the coordination polymers by X-ray powder pattern studies. The thermal stability of the polymers was also studied by a simple method, utilizing a thermogravimetric balance. The order of thermal stabilities is Cu(II) > Ni(II) > Co(II). The polymers start to decompose at a relatively low temperature.

• Bulletin of the Korean Chemical Society
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• 제23권7호
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• pp.957-963
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• 2002

We successfully synthesized the addition-type polynorbonenes (PNB) exhibiting photochromic properties and excellent thermal stability. Three norbornene-based monomers with different azobenzene moiety (R=NO2, H,OCH3) were synthesized by transesterification method. The corresponding PNB copolymers were synthesized by transition metal-catalyzed addition polymerization method, and characterized by GPC, UV-Vis spectroscopy, NMR, and thermal analysis. For comparison of the photochromic properties depending on the rigidity of polymer backbone, we prepared the polymethylmethacrylate (PMMA) copolymer with the corresponding azobenzene moiety. We investigated the photoisomerization behavior by means of optical muitichannel analyzer with Xe lamp as well as real-time UV-Vis spectroscopy with high-pressure mercury lamp. Among three PNB copolymers, a polymer with azobenzene (R=H) was the most adaptable for observation of photoisomerization behavior. It was found that the rate of photoisomerization and relaxation depended on the structure of azobenzene chromophore, rather than that of polymer backbone.

• Journal of the Korean Applied Science and Technology
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• 제12권1호
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• pp.115-118
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• 1995

Hexyltriphenylphosphonium-TCNQ(HTPP-TCNQ) complex for preparing organic thin film by Langmuir-Blodgett technique was synthesized from LiTCNQ and Hexyltriphenylphosphonium bromide. The structure of the new complex was confirmed by $^{1}H$ NMR, $^{31}P$ NMR, IR, UV spectroscopies, TGA and elemental analysis. A stability to spreading solvent, which is acetonitrile, ethylacetate, ethanol and acetonitrile-ethylacetate(1:1 v/v), of HTPP-TCNQ complex was investigated by UV-visible spectrophotometer. The complex was stabilized in acetonitrile, ethylacetate, aceton, acetonitrile-ethylacetate (1:1 v/v) for 6 h.

• Bulletin of the Korean Chemical Society
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• 제23권8호
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• pp.1073-1077
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• 2002

Binding of dodecyl trimethylammonium bromide (DTAB) to human and bovine hemoglobin and globin samples has been investigated in 50 mM glycine buffer pH = 10, I = 0.0318 and 300 K by equilibrium dialysis and temperature scanning spectrophotometry techniques and method for calculation of average hydrophobicity. The binding data has been analyzed, in terms of binding capacity concept $({\theta})$, Hill coefficient (nH) and intrinsic Gibbs free energy of binding $({\Delta}Gbv).$ The results of binding data, melting point (Tm) and average hydrophobicity show that human hemoglobin has more structural stability than bovine hemoglobin sample. Moreover the results of binding data analysis represent the systems with two and one sets of binding sites for hemoglobin and globin, respectively. It seems that the destabilization of hemoglobin structure due to removal of heme group, is responsible of such behavior. The results indicating the removal of heme group from hemoglobin caused the depletion of first binding set as an electrostatic site upon interaction with DTAB and exposing the hydrophobic patches for protein.

• Bulletin of the Korean Chemical Society
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• 제32권3호
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• pp.1011-1016
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• 2011

A series of thiadiazole derivatives were synthesized with differently substituted benzoic acids which were cyclized to give differently substituted thiazolidin-4-one. Elemental analysis, IR, $^1H$ NMR, $^{13}C$ NMR and mass spectral data confirmed the structure of the synthesized compounds. The derivatives of these moieties were evaluated for anticonvulsant activity by MES model and neurotoxicity by rotarod method. The synthesized compounds showed good potential for anticonvulsant activity besides this, the compounds also showed neurotoxic effect. It was observed that compounds with $OCH_3$ at 3, 4 position of phenyl ring [5(a-l)] showed less protection against convulsions as compared to compounds having unsubstituted phenyl ring [4(a-l)].

• Bulletin of the Korean Chemical Society
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• 제31권10호
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• pp.2783-2785
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• 2010

Searching for new molecular radicals which are believed to play an important role as reaction intermediates in aromatic chain reactions, we have applied the technique of corona excited supersonic expansion employing a pinhole-type glass nozzle to obtain the vibronic spectrum from the corona discharge of precursor 3,5-difluorotoluene with a large amount of inert carrier gas helium. An analysis of the observed spectrum revealed that many vibronic bands are from other isomeric difluorobenzyl radicals generated in the jet by migration of the fluorine atom or methylene group to the adjacent position in the 3,5-difluorobenzyl radical. A possible mechanism was proposed for the formation of other isomers by using a bridged cyclic intermediate structure.

• Bulletin of the Korean Chemical Society
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• 제30권8호
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• pp.1845-1850
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• 2009

We have performed replica-exchange molecular dynamics (REMD) simulations on the dimer formation of fibrilforming segments of $\alpha$-Synuclein (residues 71 - 82) using implicit solvation models with two kinds of force fields- AMBER parm99SB and parm96. We observed spontaneous formation of dimers from the extensive simulations, demonstrating the self-aggregating and fibril forming properties of the peptides. Secondary structure profile and clustering analysis showed that dimers with antiparallel $\beta$-sheet conformations, stabilized by well-defined hydrogen boding, are major species corresponding to global free energy minimum. Parallel dimers with partial $\beta$-sheets are found to be off-pathway intermediates. The relative instability of the parallel arrangements is due to the repulsive interactions between bulky and polar side chains as well as weaker backbone hydrogen bonds.

• Bulletin of the Korean Chemical Society
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• 제24권7호
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• pp.899-900
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• 2003

• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.815-818
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• 2010

Free base meso-tetraarylporphyrins ($H_2T(X)PP$) react with tellurium(IV) chloride ($TeCl_4$) in mild conditions for formation sandwich intermediate sitting-atop (i-SAT) complexes, [$TeCl_4(H_2T(X)PP)_2$]. $^1H$ NMR, $^{13}C$ NMR, UV-vis, FT-IR and elemental analysis were used for characterization of the products. In the proposed structure of the i-SAT complexes, four pyrroles of each porphyrin ring are tilted alternatively up and down and this appropriates suitable orientation of lone pairs of two pyrrolenine nitrogens for electron donation to a tellurium center. $^1H$ NMR and FT-IR results showed that in the produced complex, hydrogen atoms of porphyrin macrocycles remained on the pyrrole nitrogens.

• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.793-797
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• 2010

A series of 2-aminothiazoles derivatives have been synthesized and tested for in vitro antibacterial activity on different microorganisms. Syntheses have been carried out following simple methodology in excellent isolated yields. The structure and purity of the original compounds were confirmed by IR, NMR, Mass spectroscopy, and elemental analysis. All compounds were tested for antibacterial activity against S. aureus, S. pyogenes, E. coli, P. aeruginosa, S. typhi and V. parahaemolyticus. These preliminary results indicate that some of compounds are exhibiting good activity.